Dirt material converts waste heat directly to electricity

SummarySo-called thermoelectric materials are able to directly convert differences in temperature to electrical voltage.

In a breakthrough that can revolutionise power generation, scientists claim to have created an inexpensive new material from common dirt which directly converts waste heat into an electrical current.

Researchers produced the groundbreaking substance using commonly found materials and believe it could spark a revolution in eco-friendly power generation by taking waste heat from a range of common sources and converting it directly to electricity, the 'Daily Mail' reported.

So-called thermoelectric materials are able to directly convert differences in temperature to electrical voltage, and vice versa.

These are potentially important, scientists say, because the vast majority of heat that is generated from, for example, a car engine, is lost through the tail pipe.

It's the thermoelectric material's job to take that heat and turn it into something useful, like electricity.

Such materials have been made before, but previous examples have been derived from rare and sometimes toxic elements, often by way of expensive synthesis procedures.

Donald Morelli, a professor of chemical engineering and materials science at Michigan State University, led the team which developed the material based on natural minerals known as tetrahedrites.

"What we've managed to do is synthesise some compounds that have the same composition as natural minerals," said Professor Morelli, director of MSU's Centre for Revolutionary Materials for Solid State Energy Conversion.

"The mineral family that they mimic is one of the most abundant minerals of this type on Earth - tetrahedrites.

By modifying its composition in a very small way, we produced highly efficient thermoelectric materials," Morelli said.

"Typically you'd mine minerals, purify them into individual elements, and then recombine those elements into new compounds that you anticipate will have good thermoelectric properties. But that process costs a lot of money and takes a lot of time.

Our method bypasses much of that," Morelli said.

The MSU researchers' method involves the use of very common materials, grinding them to a powder, then using pressure and heat to compress into usable sizes.

"It saves tremendously in terms of processing costs," Morelli added. The research was published in the journal Advanced Energy Materials.